Exploring the reactivity of alpha-triorganylsilyl alpha-diazo esters : C-H activation, insertion reactions, and rearrangements
type: CreativeWork
description: The metal-catalyzed reactions of Alpha-triorganylsilyl Alpha-diazo esters have been studied, with an emphasis on: · Dirhodium(II)-catalyzed insertions of Alpha-triorganylsilyl Alpha-diazo esters into activated C-H bonds. · Dirhodium(II)-catalyzed reactions of -triorganylsilyl Alpha-diazo esters with various acyclic and cyclic carbonyl precursors. · The syntheses of Alpha-silyl-substituted Alpha-keto esters, their corresponding hydroxy esters and hydroxy acids, in addition to investigating dirhodium(II)-catalyzed O-H insertion reactions. Insertion of benzyl and ethyl 2-triorganylsilyl 2-diazoacetates into activated C-H bonds adjacent to oxygen, such as in tetrahydrofuran, was possible using dirhodium(II) acetate , albeit in moderate yields (up to 50% yield). When the chiral Davies catalyst was used, benzyl 2-tetrahydro-2-furanyl-2-trimethylsilylacetate was obtained in 58% ee. Ring expanded products were isolated from the reaction of benzyl Alpha-triorganylsilyl Alpha-diazoacetate with oxetane, attributed to a Stevens rearrangement. The dirhodium(II)-catalyzed reaction of Alpha-triorganylsilyl Alpha-diazoacetates proceeded well with various acyclic and cyclic ketones, affording dioxolanones in up to 98% yield. The effect of the structure of the diazo compound on the formation of the dioxolanones was investigated, and various novel silyl-substituted diazo precursors were synthesized for this purpose. A silylated enol ether competes with the formation of a dioxolanone, depending on the electronic and steric properties of the ester functionality. Two routes for the synthesis of Alpha-silyl-substituted Alpha-hydroxy acids were envisioned, comprising dirhodium(II)-catalyzed oxygen transfer and dirhodium(II)-catalyzed O-H insertions. Reactions of Alpha-triorganylsilyl Alpha-diazo esters with propylene oxide afforded 2-silyl-2-oxoacetates in up to 95% yield. These were converted into their corresponding enantiomerically-pure hydroxy acids via reduction using NaBH4, enantiome…
abstract: The metal-catalyzed reactions of Alpha-triorganylsilyl Alpha-diazo esters have been studied, with an emphasis on: · Dirhodium(II)-catalyzed insertions of Alpha-triorganylsilyl Alpha-diazo esters into activated C-H bonds. · Dirhodium(II)-catalyzed reactions of -triorganylsilyl Alpha-diazo esters with various acyclic and cyclic carbonyl precursors. · The syntheses of Alpha-silyl-substituted Alpha-keto esters, their corresponding hydroxy esters and hydroxy acids, in addition to investigating dirhodium(II)-catalyzed O-H insertion reactions. Insertion of benzyl and ethyl 2-triorganylsilyl 2-diazoacetates into activated C-H bonds adjacent to oxygen, such as in tetrahydrofuran, was possible using dirhodium(II) acetate , albeit in moderate yields (up to 50% yield). When the chiral Davies catalyst was used, benzyl 2-tetrahydro-2-furanyl-2-trimethylsilylacetate was obtained in 58% ee. Ring expanded products were isolated from the reaction of benzyl Alpha-triorganylsilyl Alpha-diazoacetate with oxetane, attributed to a Stevens rearrangement. The dirhodium(II)-catalyzed reaction of Alpha-triorganylsilyl Alpha-diazoacetates proceeded well with various acyclic and cyclic ketones, affording dioxolanones in up to 98% yield. The effect of the structure of the diazo compound on the formation of the dioxolanones was investigated, and various novel silyl-substituted diazo precursors were synthesized for this purpose. A silylated enol ether competes with the formation of a dioxolanone, depending on the electronic and steric properties of the ester functionality. Two routes for the synthesis of Alpha-silyl-substituted Alpha-hydroxy acids were envisioned, comprising dirhodium(II)-catalyzed oxygen transfer and dirhodium(II)-catalyzed O-H insertions. Reactions of Alpha-triorganylsilyl Alpha-diazo esters with propylene oxide afforded 2-silyl-2-oxoacetates in up to 95% yield. These were converted into their corresponding enantiomerically-pure hydroxy acids via reduction using NaBH4, enantiome…
author: Saladin, Sandra
language: eng
keywords: info:eu-repo/classification/ddc/540, Ester, Diazoverbindungen, Silylgruppe, Einschiebungsreaktion, Rhodiumkomplexe, Katalysator, Chemie, rhodium, carbenoids, diazo ester, C-H insertion, carbonyl ylides, O-H insertion
date published: 2004
date modified: 2026-07-30T19:42:48Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University